Every Part Every Interval, also known as EPEI or EPEx, represents the frequency that different parts are produced or services provided within a fixed repeating schedule. This fixed repeating schedule is often graphically portrayed, for training purposes and as a scheduling visual control, as a wheel, with the different products represented by alphas (A, B, C…) and the wheel indexed clockwise to follow the intended sequence.
When most people hear the word average they think normal, typical, boring. But, in many cases that is very far from the truth.
Averages can not only be interesting, but also impossible!
Consider the call center that measures average response time. The average response time is less than their target, so they must be doing pretty good, right???
Wrong!
I am saddened to l
earn of the passing of George E.P. Box. I never met him, but like many, I knew him through his work. I have read and reread several of his books. They are some of my most prized possessions.
The seminal book on lean, The Machine that Changed the World, spent many words, tables, and figures on the subject of productivity (as well as, of course, quality).
Why?
Productivity is one of the critical few measures that reflect the “leanness” of a process, value stream or enterprise. It captures how effectively an organization uses its resources, and it’s usually a meaningful way to compare performance over time and between entities.
Lean oriented questions tend to be straightforward, but not necessarily easy.
Looking for something to do? Why not run a continuous variable gage repeatability and reproducibility test? Our experience is that while many organizations have their key measurement devices on a calibration schedule, calibration simply isn’t enough. Gage R&R tests provide insights into how the users interact with measuring equipment and can uncover issues such as: bias, linearity issues, accuracy issues, and of course, repeatability and reproducibility issues.
Container capacity (Cc) is one of the four basic variables within the generic kanban sizing calculation. However, Cc is often NOT treated as variable, but more as a constant, pre-determined quantity, especially if the lean practitioner seeks to use existing supplier packaging, reusable dunnage, standard bin sizes or racks, etc.
Often that is the best, least waste way. Although, sometimes it is not prudent from an inventory management and/or ergonomic perspective.
Honestly, the last bit of formal and substantive math that I worked with was back in college. Many, many years ago, I received a B.S. in Mathematics, but other than the diploma, there is little physical or intellectual (!!) evidence that would support this reality.
My former classmates might say the same was true way back when. My kids? Well, they used to hesitate before asking me to help them with their math homework.
Many folks use the terms efficiency and productivity interchangeably.
They are not interchangeable. They are not equivalent.
Heck, they’re not even synonyms – even though Thesaurus.com thinks so.
Technically, productivity is a ratio of (good) outputs to inputs and efficiency is the ratio of actual output to standard output. Lean practitioners are typically and more appropriately concerned about productivity. As the famous Art Byrne, former CEO of Wiremold, said, “Productivity = Wealth.”
